Iryna Rybakova is horribly aware that the front line is inching toward Kramatorsk. Having served in eastern Ukraine for several years, she has watched her units being pushed from one strategic hub after another. But she said the past few weeks have been “insane.” The city remains one of Ukraine’s last strongholds in the Donbas region, but the Russians are getting dangerously close. Nearly all of the city’s bridges have been destroyed, and barrages of guided bombs and drones are now a daily reality. “The attacks happen dozens of times a day. Dozens of cars, utility buildings, residential buildings, administrative...